A procedure for non‐proportional size scaling of the strength of concrete based on the weakest‐link statistics is proposed to synchronize strength data from specimens of different geometries and ...different loading modes. The procedure relies on proportional size scaling of strength to determine the parameters of the statistical model and often on finite element analysis to calculate the coefficient of the equivalent strength. The approach for non‐proportional size scaling is capable to synchronize the uniaxial strength data of concrete from uniaxial tensile specimens and 3‐point bending specimens, or the biaxial tensile strength data of circular plates in different loading mode. The non‐transference of the uniaxial strength data to the biaxial strength data is unclear in its mechanism but possibly due to the variation of statistical distribution of microcracks with stress states in different specimens.
Although the clinical features of the Isocitrate dehydrogenase 2 (IDH2) mutation in acute myeloid leukemia (AML) have been characterized, its prognostic significance remains controversial and its ...stability has not been investigated. We analyzed 446 adults with primary non-M3 AML and found IDH2 R172, R140 and IDH1 R132 mutations occurred at a frequency of 2.9, 9.2 and 6.1%, respectively. Compared with wild-type IDH2, mutation of IDH2 was associated with higher platelet counts, intermediate-risk or normal karyotype and isolated +8, but was inversely correlated with expression of HLA-DR, CD34, CD15, CD7 and CD56, and was mutually exclusive with WT1 mutation and chromosomal translocations involving core-binding factors. All these correlations became stronger when IDH1 and IDH2 mutations were considered together. Multivariate analysis revealed IDH2 mutation as an independent favorable prognostic factor. IDH2(-)/FLT3-ITD(+) genotype conferred especially negative impact on survival. Compared with IDH2 R140 mutation, IDH2 R172 mutation was associated with younger age, lower white blood cell count and lactate dehydrogenase level, and was mutually exclusive with NPM1 mutation. Serial analyses of IDH2 mutations at both diagnosis and relapse in 121 patients confirmed high stability of IDH2 mutations. In conclusion, IDH2 mutation is a stable marker during disease evolution and confers favorable prognosis.
This work concerns the complex oscillatory singularities revealed in Williams's asymptotic solutions to stress fields around arbitrary interface cracks, which are the foundation of phenomenological ...interface fracture mechanics. First, we highlight the fatal discrepancy between the asymptotic stress fields for cracks in a homogeneous material obtained by assigning an identical material on both regions embracing an interface crack, and the solutions directly derived from cracks in a single material. Next, following a brief introduction to Williams's formulation process, we adopt the method of repeatedly eliminating variables instead of solving the determinant equation for the coefficient matrix to reformulate the asymptotic analysis of stress fields at arbitrary interface cracks. The resultant stresses get rid of oscillatory character. Further, under two specific loading conditions, namely, remotely uniaxial tension or shear, non‐oscillatory and non‐singular asymptotic solutions to stress fields around interface cracks are obtained.
Soil infiltrability, or infiltration capacity, is the rate at which water penetrates into the soil at a rate directly controlled by soil factors alone. The infiltrability is of great importance in ...understanding and managing hydrological processes, crop water supply, irrigation, and soil erosion. The infiltration dynamics measured with the run off-on-out (ROOO) method follows the changes in infiltrability during the infiltration process under rainfall conditions. In this study, the ROOO method was used to quantitatively measure the soil infiltrability under three rainfall intensities (20, 40 and 60
mm/h) and three antecedent soil moisture contents (2.6%, 10.4% and 19.5%, equivalent to 7.5% (air-dry), 30% and 60% of field capacity, respectively, of a clay loam soil. The soil infiltrability determined by the ROOO method decreased with increase in initial soil water content, due to the lower hydraulic gradient at the wetting front. Surface seal formation due to raindrop impact had a significant influence on soil infiltrability and was related to the soil water content. The faster wetting rate of drier soil under higher rainfall intensities, or when using the double-ring infiltrometer for comparison, caused severe aggregate breakdown to promote surface sealing, and significant decrease in soil infiltrability. Cumulative infiltration increased rapidly at the beginning of the infiltration process and then increased approximately linearly with time as the infiltration rate approached to constant. The rate of increase in cumulative infiltration was less under higher initial soil water contents, especially in the initial rainfall stage. Moreover, lower rainfall intensity resulted in higher infiltration rates and greater cumulative infiltration. The soil infiltrability processes measured with the ROOO method were fitted better by Kostiakov, Horton and Philip infiltration models than those measured by the double-ring infiltrometer method. The ROOO method provided reliable data for the entire infiltration process without the limitations of conventional rainfall simulation during the initial phase or of the drawbacks of the double-ring infiltrometer method. The results will have introductory meanings to further studies along this line.
The contribution of garbage burning (GB) emissions to chloride and PM2.5 in the Mexico City Metropolitan Area (MCMA) has been investigated for the period of 24 to 29 March during the MILAGRO-2006 ...campaign using the WRF-CHEM model. When the MCMA 2006 official emission inventory without biomass burning is used in the simulations, the WRF-CHEM model significantly underestimates the observed particulate chloride in the urban and the suburban areas. The inclusion of GB emissions substantially improves the simulations of particulate chloride; GB contributes more than 60% of the observation, indicating that it is a major source of particulate chloride in Mexico City. GB yields up to 3 pbb HCl at the ground level in the city, which is mainly caused by the burning of polyvinyl chloride (PVC) in the garbage. GB is also an important source of PM2.5, contributing about 3–30% simulated PM2.5 mass on average. More modeling work is needed to evaluate the GB contribution to hazardous air toxics, such as dioxin, which is found to be released at high level from PVC burning in laboratory experiments.
The contribution of HONO sources to the photochemistry in Mexico City is investigated during the MCMA-2006/MILAGO Campaign using the WRF-CHEM model. Besides the homogeneous reaction of NO with OH, ...four additional HONO sources are considered in the WRF-CHEM model: secondary HONO formation from NO2 heterogeneous reaction with semivolatile organics, NO2 reaction with freshly emitted soot, NO2 heterogeneous reaction on aerosol and ground surfaces. The WRF-CHEM model with the five HONO sources performs reasonably well in tracking the observed diurnal variation of HONO concentrations. The HONO sources included are found to significantly improve the HOx (OH+HO2 ) simulations during daytime and the partition of NO/NO2 in the morning. The HONO sources also accelerate the accumulation of O3 concentrations in the morning by about 2 h and subsequently result in a noticeable enhancement of O3 concentrations over the course of the day with a midday average of about 6 ppb. Furthermore, these HONO sources play a very important role in the formation of secondary aerosols in the morning. They substantially enhance the secondary organic aerosol concentrations by a factor of 2 on average in the morning, although they contribute less during the rest of the day. The simulated particle-phase nitrate and ammonium are also substantially enhanced in the morning when the four HONO sources are included, in good agreement with the measurements. The impact of the HONO sources on the sulfate aerosols is negligible because of the inefficient conversion of H2 SO4 from SO2 reacting with OH.
Currently available drug delivery systems for oral diseases suffer from short retention time and poor local concentrations at the target site. A biodegradable stimulus-responsive hydrogel was ...synthesized in the present study to evaluate its application as an environmentally sensitive carrier for on-demand intraoral drug delivery. The hydrogel was synthesized from diacrylate-containing polyethylene glycol–based scaffolds and a cysteine-terminated peptide crosslinker (CGPQG↓IWGQC) via a Michael-type addition reaction. Because CGPQG↓IWGQC can be cleaved by matrix metalloproteinase 8 (MMP-8), minocycline hydrochloride, bovine serum albumin, or an antibacterial peptide (KSL) was incorporated into the scaffolds to evaluate the MMP-8-responsive release behavior of the on-demand drug delivery system. Hydrogel characterization and gelation kinetics were examined with gel time, Fourier-transform infrared spectroscopy, scanning electron microscopy, and measurements of rheologic parameters. Degradation behavior and MMP-8-responsive drug release were performed by high-performance liquid chromatography and protein-specific assay. Biocompatibility evaluation indicated that the hydrogels were noncytotoxic. Antibacterial testing demonstrated that the released drugs were able to maintain bioactivity. Taken together, these results suggest that the MMP-8-sensitive hydrogel is a promising candidate for on-demand intraoral localized drug delivery. Because MMP-8 is one of the most important biomarkers for periodontitis, the MMP-8-responsive hydrogel has potential to be used for in situ adaptive degradation in response to chronic periodontitis and peri-implantitis. This notion has to be tested in animal models of periodontal disease.
Organic aerosol concentrations are simulated using the WRF-CHEM model in Mexico City during the period from 24 to 29 March in association with the MILAGRO-2006 campaign. Two approaches are employed ...to predict the variation and spatial distribution of the organic aerosol concentrations: (1) a traditional 2-product secondary organic aerosol (SOA) model with non-volatile primary organic aerosols (POA); (2) a non-traditional SOA model including the volatility basis-set modeling method in which primary organic components are assumed to be semi-volatile and photochemically reactive and are distributed in logarithmically spaced volatility bins. The MCMA (Mexico City Metropolitan Area) 2006 official emission inventory is used in simulations and the POA emissions are modified and distributed by volatility based on dilution experiments for the non-traditional SOA model. The model results are compared to the Aerosol Mass Spectrometry (AMS) observations analyzed using the Positive Matrix Factorization (PMF) technique at an urban background site (T0) and a suburban background site (T1) in Mexico City. The traditional SOA model frequently underestimates the observed POA concentrations during rush hours and overestimates the observations in the rest of the time in the city. The model also substantially underestimates the observed SOA concentrations, particularly during daytime, and only produces 21% and 25% of the observed SOA mass in the suburban and urban area, respectively. The non-traditional SOA model performs well in simulating the POA variation, but still overestimates during daytime in the urban area. The SOA simulations are significantly improved in the non-traditional SOA model compared to the traditional SOA model and the SOA production is increased by more than 100% in the city. However, the underestimation during daytime is still salient in the urban area and the non-traditional model also fails to reproduce the high level of SOA concentrations in the suburban area. In the non-traditional SOA model, the aging process of primary organic components considerably decreases the OH levels in simulations and further impacts the SOA formation. If the aging process in the non-traditional model does not have feedback on the OH in the gas-phase chemistry, the SOA production is enhanced by more than 10% compared to the simulations with the OH feedback during daytime, and the gap between the simulations and observations in the urban area is around 3 μg m−3 or 20% on average during late morning and early afternoon, within the uncertainty from the AMS measurements and PMF analysis. In addition, glyoxal and methylglyoxal can contribute up to approximately 10% of the observed SOA mass in the urban area and 4% in the suburban area. Including the non-OH feedback and the contribution of glyoxal and methylglyoxal, the non-traditional SOA model can explain up to 83% of the observed SOA in the urban area, and the underestimation during late morning and early afternoon is reduced to 0.9 μg m−3 or 6% on average. Considering the uncertainties from measurements, emissions, meteorological conditions, aging of semi-volatile and intermediate volatile organic compounds, and contributions from background transport, the non-traditional SOA model is capable of closing the gap in SOA mass between measurements and models.
van der Waals epitaxy (vdWe) method has recently attracted considerable interest due to its extensive application in the growth of layered structure materials. However, the growth process of vdWe is ...not completely understood. Here, we report the controlled growth process of Bi2Se3 nanobelts and study their photoresponse behaviour. The average length of nanobelts increases from 7 μm to 17 μm by adjusting the temperature of Bi2Se3 powder from 520 °C to 530 °C, however the average length becomes saturated with further increasing the source material temperature over 530 °C. Such a change can be attributed to the competition between the process of Bi2Se3 molecule diffusion and the process of crystal formation-related chemical reaction, leading to a symmetrically studying for the growth process of catalyst-free vdWe growth of Bi2Se3 nanobelts. The photodetectors based on these Bi2Se3 nanobelts show excellent device performance in the near-infrared light range, including an ultra-fast photoresponse (trsing ≈ 37 ms, tdecay ≈ 62 ms), a high responsivity of 10.1 mA/W and a high detectivity of 4.63 × 108 Jones. This high device performance could be related to the excellent carrier transport properties as Bi2Se3 nanobelt photodetectors also demonstrate a great potential for fabricating flexible and wearable electronics by still showing stable photoresponse after bending the device for 200 times.
•We demonstrate a controlled catalyst-free vdWe process of Bi2Se3 nanobelts.•A high-performance flexible NIR photodetector based on Bi2Se3 nanobelts is measured and analyzed for the first time.•The NIR photodetector shows ultra-fast photoresponse (tr ≈ 37 ms, td ≈ 62 ms), a high responsivity and detectivity
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